Computerization of certain aspects of vehicles has led to a shift from completely manual control of vehicles to vehicles in which drivers are provided with varying levels of assistance. Some systems are passive in nature. In a passive system, a condition is detected, and the driver is warned of the condition. Other systems are active in nature. In an active system, a condition is detected and the vehicle assumes control of a certain system or modifies the control inputs made by the driver.
Some driver assistance systems are intended to warn drivers as to potential collisions. Collision warning systems that are currently in wide use rely on detection and ranging systems that utilize technologies such as Sonar, Radar, and Lidar. The signals generated by the detection and ranging system are used as a basis for determining whether a collision is imminent.
Collision warning systems that are based on vehicle-to-vehicle (V2V) communications are under development. One example of V2V communication is a system in which vehicles exchange a basic safety message or “BSM.” The BSM that is broadcast by a vehicle can contain a number of data elements that describe various aspects of the operation of the vehicle or provide information about the vehicle itself. As one example, the BSM can include location and trajectory information. As another example, the BSM can include information that describes the vehicle type and size for the vehicle. In any event, the BSM may be used in collision warning systems.